1. Field
Example embodiments generally relate to a pipe clamp apparatus adapted to automatically adjust to pipes of variable diameters, and a torque module for the pipe clamp apparatus for applying torque thereto.
2. Related Art
Conventionally at an oil rig site, various diameters of piping are used in order to extract fossil fuels deep beneath the earth's crust. Various sections of different diameters are connected via drill collars on the inward direction into the well, as well as on the extraction direction. The time it takes, “connection time”, delays extraction of oil and is a significant cost to drillers.
Accordingly, a site will typically have a number of different sized drill slips or drill collars to account for the different diameter piping used; i.e., a different sized drill slip or casing slip is used with each change in pipe diameter. Often this can mean up to 5 to 7 different diameter pipe handling devices such as slips, drill collars, tongs, as well as wasted time changing between these devices or changing the devices to different pipe sizes.
There are two, basic, conventional clamping methods used to hold pipe during torque operations on the pipe. The pipe is torqued at every tool joint or pipe joint, and a joint is present on drill pipe at about every thirty feet; thus requiring a torque operation at every joint. Drilling operations typically range from about 10,000 to 20,000 in depth, so hundreds of these torque operations are performed during the drilling process. The pipe must be clamped each time a torque operation is performed thereon.
One clamping method employs two clamp dies, one clamp die located on each side of the pipe in a holder. This design applies all of the force in a small area about 1″ by 5″ on either side of the pipe; if the applied force is too high in this small area it will cause the pipe to become deformed, or “egg-shaped”, damaging the pipe.
The second conventional clamping method employs three (3) fixed clamp dies located in a holder set at a static mid-range radius in an effort to try and clamp different diameter pipes and distribute the force over a greater area. On pipe having a smaller diameter (and hence smaller radius), and due to the preset radius of the dies in the holder, the smaller pipe only makes contact on the inside edge of the clamp dies only. Conversely, if the pipe diameter (and hence radius) is larger, the outside dies in the clamp holder will contact on the outside edge only. This becomes an issue, as pressure is not distributed evenly on the clamps during the torque operations.
In both design cases, if the pipe diameter changes, inserts must be either added or removed from the fixed jaw clamps in an effort to compensate for the radius change effect. Further, as the clamps provide only two points of pressure on the pipe, and not a uniform pressure, there is the possibility of slippage and/or deformation of the pipe under intense forces (typically in upwards of 100,000 ft-lbs) applied by the clamps to hold the pipe in place.
Conventionally, the torque applied to these clamps is by way of a cylinder located in a torque module. The cylinder design is used to rotate the clamp device. This torque system is limited to 32 to 37 degrees of rotation maximum. This is due to what is known as a cam over effect caused by the use of a cylinder. A cam over effect can be understood where as the cylinder pushes around the arc rotating the pipe, typically about an arc of around 37 degrees, the cylinder can no longer be returned to its starting point. The cylinder will attempt to come straight across the arc and not follow the arc when it is returned. This conventional cylinder design in the torque module is also limited to rotate or work one sided, i.e. it cannot go both clockwise (CW) and counter-clockwise (CCW) from a neutral position, only CW or CCW only-one direction. This limitation will cause what is referred to as the “breakout operation” (i.e., disconnect) to be a two-step process instead of a single step. To breakout, the conventional torque module with cylinder initially has to rotate to 35 degrees, then the clamp is applied to the pipe, and finally the clamped pipe under torque is rotated back. This two step process takes twice as long. Moreover, the 37 degree limitation can also cause the torque process to require multiple movement steps, as a rotation may require greater than a 37 degree movement on the pipe with the clamp.